Infiltration, Hydraulic Conductivity, and Resistance to Water-Drop Impact of Clod Beds as Affected by Chemical Treatment1

D. M. Gabriels,

W. C. Moldenhauer and

Don Kirkham2

Abstract

Abstract

Chemicals were sprayed on large dry surface clods (8 to 20 mm) and small surface clods (2 to 8 mm) of a Clarion loam to test their effectiveness in preventing erosion during rainfall. The small clods were initially wetted with 15% water on a soil weight basis and mixed with bitumen emulsions. The large and small clods were subjected to a 6.35-cm-per-hour simulated rainfall under controlled conditions in the laboratory. Simultaneously with the measurements of infiltration rate, determinations were made of (i) the starting time for initial runoff, (ii) energy needed to initiate runoff, (iii) runoff rate, (iv) total soil loss, and (v) final soil loss rate.

Surface applications of most of the soil conditioners on large clods applied at high enough rates kept the infiltration rate high and prevented runoff on a 9% slope. Polyvinyl alcohol and polyacrylamide prevented any soil loss during 90 min.

Surface applications with bitumen emulsions were also highly effective in preventing erosion of large clods but were less effective for small clods. When the bitumen emulsions were mixed with the small clods, the saturated hydraulic conductivity was very high. The infiltration rate was low because water would not enter the clod bed and stable clods were carried in the runoff water.

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